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https://issues.apache.org/jira/browse/CASSANDRA-13292?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16840218#comment-16840218
 ] 

Benedict commented on CASSANDRA-13292:
--------------------------------------

https://github.com/rurban/smhasher

> Replace MessagingService usage of MD5 with something more modern
> ----------------------------------------------------------------
>
>                 Key: CASSANDRA-13292
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-13292
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Legacy/Core
>            Reporter: Michael Kjellman
>            Assignee: Michael Kjellman
>            Priority: Normal
>         Attachments: quorum-concurrency-reads-quorum.svg
>
>
> While profiling C* via multiple profilers, I've consistently seen a 
> significant amount of time being spent calculating MD5 digests.
> {code}
> Stack Trace   Sample Count    Percentage(%)
> sun.security.provider.MD5.implCompress(byte[], int)   264     1.566
>    sun.security.provider.DigestBase.implCompressMultiBlock(byte[], int, int)  
> 200     1.187
>       sun.security.provider.DigestBase.engineUpdate(byte[], int, int) 200     
> 1.187
>          java.security.MessageDigestSpi.engineUpdate(ByteBuffer)      200     
> 1.187
>             java.security.MessageDigest$Delegate.engineUpdate(ByteBuffer)     
> 200     1.187
>                java.security.MessageDigest.update(ByteBuffer) 200     1.187
>                   org.apache.cassandra.db.Column.updateDigest(MessageDigest)  
> 193     1.145
>                      
> org.apache.cassandra.db.ColumnFamily.updateDigest(MessageDigest) 193     1.145
>                         
> org.apache.cassandra.db.ColumnFamily.digest(ColumnFamily)     193     1.145
>                            
> org.apache.cassandra.service.RowDigestResolver.resolve()   106     0.629
>                               
> org.apache.cassandra.service.RowDigestResolver.resolve()        106     0.629
>                                  
> org.apache.cassandra.service.ReadCallback.get()      88      0.522
>                                     
> org.apache.cassandra.service.AbstractReadExecutor.get()   88      0.522
>                                        
> org.apache.cassandra.service.StorageProxy.fetchRows(List, ConsistencyLevel)   
>  88      0.522
>                                           
> org.apache.cassandra.service.StorageProxy.read(List, ConsistencyLevel)      
> 88      0.522
>                                              
> org.apache.cassandra.service.pager.SliceQueryPager.queryNextPage(int, 
> ConsistencyLevel, boolean) 88      0.522
>                                                 
> org.apache.cassandra.service.pager.AbstractQueryPager.fetchPage(int)  88      
> 0.522
>                                                    
> org.apache.cassandra.service.pager.SliceQueryPager.fetchPage(int)  88      
> 0.522
>                                                       
> org.apache.cassandra.cql3.statements.SelectStatement.execute(QueryState, 
> QueryOptions)  88      0.522
>                                                          
> org.apache.cassandra.cql3.statements.SelectStatement.execute(QueryState, 
> QueryOptions)       88      0.522
>                                                             
> org.apache.cassandra.cql3.QueryProcessor.processStatement(CQLStatement, 
> QueryState, QueryOptions) 88      0.522
>                                                                
> org.apache.cassandra.cql3.QueryProcessor.process(String, QueryState, 
> QueryOptions)     88      0.522
>                                                                   
> org.apache.cassandra.transport.messages.QueryMessage.execute(QueryState)    
> 88      0.522
>                                                                      
> org.apache.cassandra.transport.Message$Dispatcher.messageReceived(ChannelHandlerContext,
>  MessageEvent)   88      0.522
>                                                                         
> org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(ChannelHandlerContext,
>  ChannelEvent)      88      0.522
>                                                                            
> org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline$DefaultChannelHandlerContext,
>  ChannelEvent)     88      0.522
>                                                                               
> org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(ChannelEvent)
>   88      0.522
>                                                                               
>    org.jboss.netty.handler.execution.ChannelUpstreamEventRunnable.doRun()     
>   88      0.522
>                                                                               
>       org.jboss.netty.handler.execution.ChannelEventRunnable.run()      88    
>   0.522
>                                                                               
>          
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor$Worker)  
>  88      0.522
>                                                                               
>             java.util.concurrent.ThreadPoolExecutor$Worker.run()        88    
>   0.522
>                                                                               
>                java.lang.Thread.run()   88      0.522
> {code}
> Pending CASSANDRA-13291, it would be pretty easy to:
> # Switch out the hashing implementation from MD5 to implementations such as 
> adler128 and murmur3_128 (but certainly not limited to) and do some profiling 
> to compare the net improvement on latencies and CPU usage
> # As we can't switch the algorithm from MD5 without breaking things, we could 
> rev the MessagingService protocol version -- like we already do for things 
> like switching from Snappy compression -> LZ4, we could switch to the new 
> hashing implementation once all peers in the node are upgraded and support 
> the new MessagingService version.



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